Watch-crystal.



LOUIS E. 1".WACHTEB, 01' NEW YORK, N. Y.

wares-caveman To allwkom it may concern.-

Be it known that I, LOUIS E. F. WACH'I'ER, a citizen of the United States, and a resident of New York city, county of New 8 York, and State of New York, have invented certain new and useful Improvements in Watch-Crystals, of which the following is as ification.

his invention relates to crystals for the protection of the hands and dials of watches,

clocks and other instruments.

Prior to my invention crystals have been made of various transparent materials, the two most commonly used being glass and i8 celluloid. The glass crystal is very hard and not easily scratched. As a consequence it retains its transparent quality. It is, however, easily broken. The celluloid crystal on the other hand is practically unbreakable but has the disadvantage of being easily scratched, and thus decreasing its transparency.

The object of my invention is to produce a closure for the faces of watches, clocks l6 and other instruments which will have an outer surface that will not scratch, and one which can not be so broken as to expose the hands and dial which it protects.

With these and other objects in view my 80 invention comprises the forming of a crystal having its outer surface composed of glass or similar hard, transparent, mar-resisting material, and beneath it a thickness of celluloid or other similar transparent, flexible, 86 substantially non-breakable material.

thereof.

With these and other objects in view my invention consists in certain constructions, combinations and arrangements of parts, a few of the forms of WhlCh will be first described in connection with the accompanying drawings, and then the-invention particularly inted out in the appended claims.

Re erring to the drawings wherein the same reference numeral is used to indicate 0 the same part wherever it occurs,

F gure 1 1s a central longitudinal cross section of a crystal embodying one form of my invention;

Fi 2 is a similar view of a slight modification in the means of attaching the two portions of the crystal together;

lpeclncatlon of Letters Patent. Patented May 20, 1919. Application fled Rovember 18,1918. 8eria11o.262,408.

Fig. 3 is a similar view of a crystal having a flat top and a concaved under surface, together with a modified means of securing the two portions of the crystal together;

Fig. 4 is a similar view of a crystal of the same contour as Fig. 3 but showing a difierent means for uniting the two portions together; Fig. 5 is a central sectional view of a crystal in which the outer surface is convex and the inner-surface plain with the two portions forming the c stal separated except at their edges where t ey are secured together,

lg. 6 is a similar view of a modification of Fig. 5, in that both portions of the crystal'are lain, and also showing a different means or securing the .two portions togather, and

Fig. 7 is a central lon 'tudinal section of a crystal of a contour similar to Form shown Fig. 1, but with a modific-i of the means for securing the two pa; .c together.

In the drawings 10 designates the inner portion of the crystal, said portion being formed of celluloid or other similar transparent, flexible, substantially un-breakable material. 1.; 1

11 indicates the outer portion of the crystal and is formed of glass of similar transparent, hard mar-resisting material. These two portions forming the crystal may. be united together in various ways, a few' of which are illustrated in the various figures of the drawings.

In Figs. 1, 2, 3, 4 and 7 it will be noted that the opposing surfaces of the portions 10 and 11 are in contact, so that the portion 10 forms a support for the entire inner surface of the portion 11, and increases the resistance of the portion 11 a ainst breakage.

In the forms shown in Figs. 5 and 6, the two portions 10 and 11 are separated from each other, forming an air space between the two portions of the crystal which has the advantage of reventing the befog ing of the crystal w en exposed to su d'en changes of temperature.

In the form shown in Fig. 1, the two portions 10 and 11 are secured together by turning up the edge 12 around the peri hery of the ortion 11. In this form the ge 12 stops 3 ort of the upper surface of the portion 11. In the form shown in Fig. 2 the portions are secured together by a similar v be sna ped over the shoul In 1g. 5 the I edge 12 which, however, is extended up over the periphery of the upper surface 11, as indicatcd at 13.

In the form shown in both Figs. 1 and 2 the crystal is concave convex. In the form shown in Fig. 3 the crystal is plano-concave, and the two portions are secured to ether :21 forming a shoulder 14 on the edge of e portion 10, and providing the ortion 11 with a depending flange 15, which can In ig. 4 the crystal is also shown as being plano-concave, and the two portions are shown as being secured together by forming the portion 10 with a depression 16 of the diameter of the portion 11, so that a projecting rim 17 is provided on the portion' 10, and when the portion 11 is snapped into the depression 16 will engage the periphery of the ortion 11 and hold it in position.

ortion 11 is shown as concavo convex, while the portion 10 is plano. As a consequence when these two portions are secured together an air chamber 18 is formed between them which will prevent befogging. In this figure I have illustrated these two portions as being secured together by the flange 19 formed on the ortion 10 bein turned over the edge of t e portion 11. .have also shown the under surface of the portion 10 as provided with a de endindg rin 20 located just within its erip cry, a apte to rest upon the face oi the dial when the crystal is in osition. $6

In Fig. 6 I have ilustrated a form in which both.the portions 10 and 11 are plano and separated to provide an air space 18.

The two portions are shown as mounted in a ring 21 having an under portion 22 extending under the lower surface of the ortion 10, an intermediate inwardly exten ing head 23 extending between the portions 10 and 11 to se arate them, and an inwardly beveled portion 24 engaging the peri hery of the portion 11, t e portion 11 eing snapped in under this beveled portion in the same way that a glass crystal is now commonly snapped into a bezel.

In Fig. 7 the portion 11 is shown as of a greater thickness than the portion 10, and

rovided with a groove 25 in its periphery into which is forced the flange 26 formed by turnin u the edge of the portion 11.

In all t eorms of the invention just deglass an scribed it is to be noted that if the outer portion 11 is broken that the portion 10 re mains intact and protects the face covered thereby.

I realize that considerable variation is possible in the details of construction and arrangement of parts without departing from the spirit of my invention, and I therefore do not intend to limit myself to the specific form shown and described.

I claim:

1. A crystal, formed of two portions secured together, the outer portion being of hard, mar-resisting transparent material, and the under portion bein of transparent, fleiiible, substantially nonireakable materia 2. crystal formed of two portions secured to ether, the outer portion being of the under portion being of transparent, flexible, substantially non-breakable material.

3. A crystal formedof two portions secured. together, the outer portion being of hard, mar-resisting transparent material andthe under portion being of celluloid.

4. A crystal formed of two portions secured to ether, the outer, portion being of (flags an -the-under portion being of cellu- 5. A crystal formed of two portions, the outer portion being of hard, mar-resisting, transparent material and the under portion bein of transparent, flexible substantially nonreakable material, the edge of the under portion being turned up around the periphery of the up er portion to secure the two portions toget er.

6. A crystal formed of two portions secured together with their adjacent surfabes in contact, whereby the under portion will act as a support and reinforcement for the outer portion, the outer portion being of hard, mar-resisting, transparent material, and the under portion bein of transparent, flexible, substantially non-breakable mate- November, 1918.

LOUIS F. WACHTER.

Witnesses:

Jornv DARBY, E. S. ECKARDT. 

